The invention relates generally to power-driven conveyors and, more particularly, to conveyor links coupled together in series at universal joints into a linked chain.
Conveyor chains constructed of a series of connected links are used to convey articles, often in single file, through a plant. In the food processing industry, chain links are often molded out of plastic materials, which offer many advantages in sanitation over metal chain links. In some applications, a chain conveys articles horizontally in a straight line. The joints between consecutive links of a straight-running chain need to pivot only about a horizontal axis perpendicular to the direction of chain travel so that the chain can backbend and articulate about drive sprockets. In other applications, a chain must negotiate turns to one side or the other. In these applications, the chain must be able to rotate about a vertical axis, too. But other applications require that a chain be made to twist about an axis in the direction of chain travel. A universal joint between adjacent chain links gives the chain three degrees of freedom to rotate between consecutive links.
But there are problems associated with universal joints in conveyor chains. Rubbing contact between bearing surfaces at the joints, especially between like materials, can cause the chain to squeak annoyingly. Furthermore, the constant motion between the bearing surfaces can cause premature or uneven wear of the links, requiring their replacement.
Thus, there is a need for a conveyor link chain with a universal joint that runs quietly and offers a longer wear life.